1. Field of the Invention
This invention relates to a thermoelectrically adjustable magnetic head used in the magnetic reading and writing device, and its position determining mechanism.
2. Description of the Prior Art
FIG. 5 is a perspective view of a conventional magnetic head. This drawing shows that the magnetic head 1 comprises a slider 2 and a supporting spring 4. On the slider 2 is formed a read/write core 3 which reads and writes information. The supporting spring 4 pressingly retains the slider 2.
FIG. 6 is a schematic showing the structure of a magnetic disk device or a magnetic read/write device using the magnetic head of FIG. 5. The magnetic head 1 is retained on a carriage 5, and moves in the direction of a radius over a magnetic disks 6. A spindle motor 7 retains and rotates the magnetic disks 6 at a predetermined number of revolutions forming concentric plural data tracks thereon. A motor 8 moves the carriage 5 in the radial direction over the magnetic disks 6. A base 9 retains the carriage 5, spindle motor 7, and the motor 8.
The combined actions of the conventional magnetic head 1 shown in FIG. 5 and the magnetic disk device shown in FIG. 6 are as follows: Information is written in and read from a plural number of concentric data tracks on the magnetic disks 6 which are formed by the movement of the magnetic head 1 in the radial direction over the magnetic disks 6 which is driven at a predetermined number of revolutions by the spindle motor 7. The carriage 5 enables the magnetic head 1 to move onto an optional data track and make random access to any recorded data thereon.
At least one of the plural number of magnetic disks 6 is often used as positional information surface (or servo surface) for determining the positional standard for the magnetic head 1 for its movement in the radial direction over the magnetic disks 6. This is generally called the servo surface servo method, and the relative positions of the magnetic head 1 and the radial direction of the magnetic disks 6 are determined according to the positional information detected from the servo surface by a magnetic segment of the magnetic head 1 used for said purpose.
Meanwhile, the magnetic head of this kind using servo surface servo system is known as IBM Technical Disclosure Bulletin, Vol. 20, No. 8 of January 1978 issue titled "Sector Servo Method" (P3243-P3247) and also Vol. 23, No. 2 of July 1980 issue titled "Track-Locating and Following Apparatus for a Flexible Disk File" (P738-P742). The magnetic head of this kind is provided with servo information along the data on the magnetic disks whereby the servo information together with data signals is read by single transducer of signal pickup use, amplified, provided to a compensator and power driver by separating the position error signal from the data and then, the moving coil actuator is driven to hold said transducer on desired data tracks.
The magnetic head and magnetic disk device being constructed as above, the variation in the factors of exterior environment, such as temperature and the like, will cause thermal and/or mechanical distortions inducing the magnetic head 1 drift away from the center of the data tracks to result in reduced reliability in recording and reproducing information.
Although the prior art may provide a transducer for picking up servo information, it will result in a very complicated mechanism, and since a servo drive must be controlled by a motor using a moving coil the device may not be so reasonably priced as to be practical.